US3423515A - Shielded jacketing for cable junctions - Google Patents

Description

Jan. 21, 1969 F, D, EICHBERG 3,423,5l5

SHIELDED JACKETING FOR CABLE JUNCTIQNS Filed July 19, 1966 Awww/5K5 United States Patent O 3,423,515 SHIELDED .IACKETING FOR CABLE JUNCTIONS Frank D. Eichberg, Huntington Beach, Calif., assignor to Walter A. Plummer, Sherman Oaks, Calif. Filed July 19, 1966, Ser. No. 566,314 U.S. Cl. 174-36 8 Claims Int. Cl. H01b 11/06 ABSTRACT OF THE DISCLOSURE A jacket adapted to be assembled about the junction of three or more cables and held closed in assembled condition by independent interlocking seams extending lengthwise of all legs of the jacket. The jacket is formed of laminated iiexible sheet material including a main layer of non-conductive material so arranged as to encircle fully all conductors enclosed by the jacket. The jacket comprises two similar plaques of laminated material formed with seam-forming material along their opposite lateral edges and superimposed upon one another and secured together along registering slits opening lengthwise from at least one end of each plaque.

This invention relates to jacketing for cabling systems and more particularly to an improved shielded jacketing for enclosing junctions of such systems.

Cabling systems employed to connect electrical components through a network of cabling composed of one or more main trunks with branchouts present problems in situations where it is important that the cabling be shielded from extraneous electrical fields. The shielded jacketing disclosed in United States Letters Patent 2,960,- 561 granted Nov. l5, 1960, is highly satisfactory for such applications except that it presents certain problems in effectively and completely shielding certain junctions of branchouts with a main trunk.

Accordingly, there is provided by the present invention a simple easily fabricated unitary shielded jacketing assembly formed of electrically conductive material laminated to one or more main body layers of nonconductive material and including a plurality of tubular branches each equipped with interlocking seam forming means providing ready access to each branch for the removal and insertion of conductors. This jacketing assembly is so constructed as to provide a continuous electrical conductive layer surrounding the conductors in each branch throughout the junction area and for a substantial distance beyond the junction.

The invention junction assembly is fabricated from two laminated layers superimposed upon one another and notched from at least one edge to provide a plurality of branches merging with one another centrally of the assembly. The metal layers are placed in contact with one another and secured permanently in this condition along the perimeter of the notched area. Extending along the outer lateral edges of the two superimposed strips are suitable interlocking seam forming means so positioned as to provide an internal guard flap along one of the edges suflciently wide to bridge the seam when closed and having its free edge enclosed with electrically conductive material. Accordingly, when the jacketing is assembled to cabling this guard flap bridges the seam with its metalclad edge in firm contact with the juxtaposed conductive material thereby providing assurance of a continuous electrically conductive layer completely surrounding the er1- closed conductors.

A primary object of the invention is the provision of an electrically shielded jacket assembly of unitary construction readily assembled about the junction of a cable network.

Another object of the invention is the provision of an CAB Patented Jan. 21, 1969 electrically shielded unitary junction fitting having a plurality of tubular branchouts each fully enclosed by laminated sheeting having an inner layer of electrically conducting material and an outer layer of nonconductive material.

Another object of the invention is the provision of an electrically shielded jacketing closure for the junction area of cable networks having a plurality of branchouts from a main trunk section and including a readily opened and reclosed seam extending along the full length of each branch thereof.

Another object of the invention is the provision of an improved onepiece jacket assembly for enclosing and shielding cabling.

These and other more specific objects will appear upon reading the following specification and claims and upon considering in connection therewith the attached drawing to which they relate.

Referring now to the drawing in which a preferred ernbodiment of the invention is illustrated.

FIGURE l is an exploded plan view of two layers of laminated material employed in constructing one preferred embodiment of jacketing for the junction of a cable network;

FIGURE 2 is a fragmentary plan view on a smaller scale at one end of the completed assembly with its seams closed;

FIGURE 3 is a crosssectional view on enlarged scale taken along line 3 3 on FIGURE 2; and

FIGURE 4 is a fragmentary enlarged View of stitching at the inner end of the notch between two tubular sections of the assembly.

Referring to the drawings showing one preferred embodiment of the invention shielded junction assembly, designated generally 10, it will be understood that the main body is fabricated from two generally similar flexible sheets of laminated material 11, 12. Both sheets include an inner layer of electrical conductive material 13 bonded to one or more outer layers of nonconductive material 14 and 15. Thermoplastic sheeting of polyvinyl chloride, polyethylene or the like are particularly suitable for outer layer 14 as are other nonconductive materials. Inner layer 13 of conductive material may comprise aluminum foil, aluminum fabric or other conductive material effective as an electrical shield. For added strength and greater improved dielectric properties it is preferred to sandwich a 1 or 2 mil layer of polyester film material 15 commercially available under the trademark Mylar between conductive layer 13 and thermoplastic layer 14. Suitable bonding agents well known to the laminating art are employed and the resulting product possesses surprising mechanical strength and greatly enhanced dielectric properties over those exhibited by a two-layer laminate. It will be understood that all layers of the laminate are coextensive in size.

In the typical junction assembly here illustrated, sheets 11 and 12 are notched from one end edge, sheet 11 being preferably slit along the T-shaped line 16 and sheet 12 preferably having a narrow strip removed to provide the long narrow notch indicated at 17. As shown here, slit 16 and notch 17 extend lengthwise of the midportion of each strip to form tubular branches of equal size but it will be apparent that branches of unequal capacity can be formed by offsetting the notch to one side of center. The two sheets 11 and 12 are then superimposed and the opposite edges 18 and 19 of slit 16 are folded about the opposite edges of notch 17 in the manner clearly shown in FIG- URE 3. The overturned edges 18 and 19 are held in this position while being firmly and permanently secured together as by rivets or stitching 20. It will be understood that this anchors the conductive layers 13, 13 of the two laminated sheets firmly together along the entire peripheral edge of notch 17. Additional stitching 21 is applied crosswise of the inner end of notch 17 to close this area and reinforcing it to withstand strain, as well as anchoring the conductive layers in firm contact in this Zone.

The opposite lateral edges of each sheet have a pair of interlocking seam forming tapes 23, 24 bonded or heat fused to the outer plastic layer in known manner. T he free edges of each tape are formed With interlocking tongues and grooves of any suitable configuration well known to those skilled in this art, such as the tongue and groove structure shown in U.S. Patent 2,960,561.

It will be understood that one of the seam forming tapes, as 23, is secured in place inwardly of the free edge of sheet 12 to provide a guard flap 28 of laminated material amply wide to underlie and bridge the seam when closed. This guard flap serves not only to prevent conductors from interfering with the closing of the seam but more particularly the important function of providing a continuous shielding layer completely encircling the conductors enclosed by the junction assembly. To insure metal-to-metal contact between the over-lapped edges of conductive layer 13, the free edge of the guard flap is embraced by a U-shaped strip of conductive material 29. This strip together with a wire braid conductor 30 is secured in place by rivets or stitching 32. The metal braid 30 extends beyond the opposite ends of the guard flap and facilitates connecting the conductive layer 13 to a suitable grounding.

It will be appreciated from the foregoing description of assembly that a unitary structure is provided formed by a pair of similar laminated sheets permanently secured together along a notch extending inwardly from one end edge. Although as herein shown notch 17 is narrow and has it opposite edges lying parallel to one another, it will be apparent that notches of various configurations may be employed as for example a wide V-notch. In this case, the opposite lateral edges of sheets 11 and 12 would lie generally parallel to the diverging sides of the V-notch for a length of the assembly corresponding generally to the length of the notch. Various other configurations and arrangements of the notch will be understood as coming within the scope of this invention and that both ends may be notched to accommodate additional branchouts. Irrespective of the shape of the two component sheets it will be understood that these normally lie flat and fiush against one another until ready for assembly about the junction area of a cable network.

The assembly of the fitting about a junction may and usually is performed while the main trunk and branchouts of the junction being enclosed are connected to the equipment. The two component sheets of assembly 10 are opened, and then wrapped about the opposite sides of the junction area. After the guard aps have been pressed against the sides of the cable the seam forming tapes 23, 24 are pressed into interlocking engagement either by pressure applied along their mating edges or by the use of a suitable slide fastener, not shown, but customarily present on such seams. First one pair of seams and then the other is closed to complete the assembly. The wider end of the assembly snugly encloses the main trunk portion of the network whereas the smaller tubular portions at the opposite end of the assembly snugly encloses separate branchouts from the main trunk. lt will be appreciated that the assembly is preferably appropriately tailored during fabrication and that each tubular section is of the appropriate size to accommodate a particular cable network junction.

While the particular shielded jacketing for cable junctions herein shown and disclosed in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as defined in the appended claims.

I claim:

1. A unitary Y-shaped tubular junction boot providing an electrically shielded enclosure for a main group of electrical conductors at the zone of separation into two branchout groups of conductors and which unitary boot is adapted to be assembled about and removed from said groups of conductors without need for access to the ends of any of the conductors, said junction boot cornprising a pair of elongated plaques of flexible laminated sheet material superimposed on one another with each plaque having an inner layer of conductive material and an outer layer on the remotely positioned exteriors of thermoplastic non-conductive material, said superimposed plaques being -divided at one end by an intervening slit, means permanently joining said plaques together along the opposite edges of said slit with the conductive layers in direct electrical contact from end-to-end of said slit, interlocking seam-forming means along the full length of the lateral edge portions ofeach of said elongated plaques adapted to interlock with one another lengthwise of the remotely spaced lateral edges of said boot after the boot has been wrapped about the exterior of three merging groups of conductors, and each of said plaques having a guard flap the free lateral edge of which is embraced by conductive material, said guard flap underlying the adjacent one of said seam-forming means with its free lateral edge overlapping and in electrical contact -With the conductive layer of the adjacent one of said plaques.

2. A unitary junction boot adapted to provide an electrically shielded enclosure for three groups of conductors merging at a Y-junction, said junction boot being formed of two elongated strips of laminated sheeting having a main body layer of electrical insulating material and a layer of electrically conductive material, said laminated strips having their conductive layers facing one another and held in conducting contact along the opposite edges of a notch extending lengthwise through one adjacent pair of ends of said laminated strips,V each of the remotely spaced lateral edges of said laminated strips being equipped with interlocking seam forming means extending throughout the length of the junction boot and cooperating when closed to hold said boot assembled about the junction of a three-branch assembly of electrical conductors, and one lateral edge along each lateral side of said boot being embraced by conductive material bridging the interior side of said seam so as to lie in contact with the conductive layer of the other of said laminated strips when said boot is assembled about a cable network junction of conductors whereby all conductors are `fully encircled by a -continuous tubular enclosure of electrically conductive material effective as a barrier for electrical flux fields.

3. A junction boot as defined in claim 2 characterized in that one of said notches is wider than the other whereby the edges of the narrow notch are adapted to be folded about the adjacent edges of the other notch thereby to form a strong joint between the laminated sheets and to conceal the edge of wider one of said notches.

4. A unitary junction boot as defined in claim 2 characterized in that the opposed edges of said notches lie generally parallel and in closely spaced relation.

5. A unitary junction boot as defined in claim 2 characterized in that the free edges of said guard flaps are embraced by electrically conductive material and include exible braiding of conductive material extending beyond the ends of said guard flaps.

6. A unitary junction boot as defined in claim 2 characterized in that the two laminated strips lie flat and flush against one another for compact packaging and being pliant and flexible to facilitate expansion and assembly of said boot into a three-branch tubular enclosure.

7. A unitary junction boot as defined in claim 2 characterized in that said laminated strips include an inner conductive layer, an outer layer of heat-fusible thermoplastic material and an intermediate layer of film-like high dielectric material intimately ybonded together.

8. A unitary electrically shielded jacket assembly for enclosing and shielding the junction portion of a cable network of the type having its remote ends unavailable for threading through a tubular passage, said unitary assembly comprising a pair of thin flexible laminated sheets superimposed against one another and including a juxtaposed inW-ardly facing layer of conductive material and a layer of non-conductive material exteriorly thereof, said laminated sheets being notched from one end thereof and ixedly secured together along the edges of said notch so as to hold said facing layers of conductive material in firm Contact throughout the length of said notch, the juxtaposed opposite lateral edges of said laminated sheets being provided with interlocking seam-forming means from end-to-end thereof positioned to overlie an associated guard ap of said laminated material when said UNITED STATES PATENTS 5/1963 Plummer 174-36 4/1965 Gow et al. 174-72 LEWIS H. MYERS, Primary Examiner.

A. T. GRIMLEY, Assistant Examiner.

U.S. Cl. X.R. 161-48

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